In the field of tree surgery, it is frequently necessary for personnel to gain elevation to specific portions of trees for the purpose of removing branches or large limbs from the trees or in many cases removing a tree in such manner that its parts do not fall and damage adjacent structures such as buildings and objects at ground level. The method presently employed to remove limbs, branches, or to cut down the entire tree is for an operator to gain access to a working elevation in a tree by manually climbing the tree with the use of hand lines, and/or climbing spurs. In some cases, a hand line is used alone to assist the operator in gaining elevation in the tree once the hand line has been placed over a limb by any suitable method from ground elevation. In many cases tree surgery operations may be conducted in such manner that small limbs, branches may be allowed to fall to the ground after having been cut away from the tree. In other cases, however, shrubs and other plants may be located at ground level which would be damaged by falling branches. It is then necessary for operators to tie ropes to the branches prior to cutting and then manually lower the branches to ground level with the assistance of ground level personnel. This character of work is time consuming, strenuous and dangerous.
Another method of conducting tree surgery operations and the like requires the use of a suitable life device such as a mobile mounted mechanical extension arm and bucket which is capable of transporting tools and other equipment to a working elevation in a tree or relative to a pole. By the use of a mobile mounted mechanical extension arm and bucket tools and equipment can be easily transported to working elevations, however, most mechanical lift devices of this type have a limit as to the elevational height that can be gained. Further, there must be sufficient area around the tree or pole to allow the mobile life unit to be located in a satisfactory position for conducting lifting and positioning. In many cases the mobile mounted mechanical extension arm devices are supported on trucks. It may not be possible to gain access to the location of the tree or pole by a truck without causing significant surface damage, which, of course, is undesirable.
Tree surgeons and other such workers may also employ ladders to gain access to certain elevators in tree, poles, etc. Typically, ladders have height limitations and are somewhat dangerous to use.
It is seen, therefore, that there are certain disadvantages and limitations to all of the above methods for positioning equipment at working elevations in trees and relative to other structures. There is a significant possibility that personnel could fall such as when using climbing spurs, ladders, etc. When hand lines are employed the line could slip or break and a limb could break, possibly resulting in falling on personnel or damage to objects at the surface or adjacent to the tree or pole. These and a number of factors associated with various activities elevation in trees and poles can present a considerable safety hazard. Another disadvantage when work is performed at elevation in trees, on poles and other structures is the amount of time that is required to position tools and equipment at the desired elevation in comparison to the time required for personnel to perform certain types of work such as tree surgery, for example.
It is desirable, therefore, to provide apparatus that is capable of safely and efficiently climbing trees, poles and other such objects under the control of personnel remaining at ground level and, after the apparatus is securely stationed at elevation, providing motive power for positioning tools and equipment at working elevation and then conducting mechanical operations such as lowering cut tree parts and the like safely to ground level for handling by personnel at ground level. It is also desirable to provide tree or pole climbing apparatus which is capable of fastening itself securely to the tree or pole and which is not capable of becoming inadvertently deenergized and thus is absolutely prevented from completely releasing its assembly from the tree or pole until the apparatus reaches ground level.
Trees generally have a more or less straight trunk which extends from ground level to the elevation of lower limbs and then have limbs extending randomly and radially from upper portions of the tree trunk. It is desirable to provide tree climbing apparatus having the capability of traversing vertically up and down the tree as appropriate and also having the capability of traversing laterally around the tree such as for avoiding limbs that might impede vertical traversing. It is also desirable to provide the apparatus with other features to enable it to remotely conduct various desirable operations. These features may be in the form of attachments for various operations such as tree spraying, limb cutting and pruning. It is also considered appropriate to provide tree climbing apparatus that may be effectively controlled by personnel located at ground level and may also be controlled by personnel located at the working level of the apparatus.